The booing that thundered down upon Sonny Gray on Saturday night did not go unnoticed by that beleaguered starting pitcher. He heard it. He even understood it. Had he been sitting in the stands, he said, “I probably would have booed me louder.”

The remark was one of several brutally honest, self-critical comments made by the right-hander after his terrible performance allowed the Red Sox to jump off to a quick start and pound the Yankees, 11-0, in front of the largest crowd at Yankee Stadium this year, 47,125.

Gray, the weak link of a five-man rotation that includes two rookies, allowed six runs in only two and one-third innings. A first-inning grand slam by Rafael Devers set the tone for another lopsided home loss to Boston that Gray started.

His earned run average at home is 8.25 this year, and against the Red Sox over all in his career it is 6.75.

Such poor numbers for any Yankee pitcher — against Boston and at home — cannot be overlooked by the front office. Brian Cashman, the general manager, is scouring the rest of baseball for a deal to upgrade the starting rotation before the July 31 deadline.

“I feel like we’re the best team in baseball four out of five days, and then to come out and do that,” Gray said. “It’s embarrassing,” he added.

Chris Sale, the Red Sox ace, stood in striking contrast to Gray. Sale baffled the Yankees lineup with perhaps his best performance of the year. He allowed only one hit over seven innings, issued one walk and struck out 11.

He improved to 2-0 against the Yankees this season, and he lowered his career earned run average against them to 1.61, the lowest by any pitcher against the Yankees who has made at least 10 starts against them in the live-ball era.

Before the game, Dave Dombrowski, the general manager of the Red Sox, spoke to reporters and revealed that he had spoken extensively with Cashman the day before. It was a cordial chat, no doubt, but surely no substantive strategic plans were divulged.

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Red Sox center fielder Jackie Bradley Jr. turning a potential extra-base hit by Aaron Hicks into an out in the third inning on Saturday night.CreditJulie Jacobson/Associated Press

While their two teams compete on the field, Dombrowski and Cashman are in competition to improve their rosters through the trade market. Even though they have the two best records in baseball, neither team can shake the other in the race for the American League East crown. A significant trade might create separation.

According to what Dombrowski told reporters, trades could start happening sooner than normal. He said he had engaged in conversations with many teams, including a few on Saturday, and noted that the teams looking to trade an established star for prospects were motivated to deal quickly.

“Some of them have indicated that they are prepared to move forward at any time,” Dombrowski said. “I think more so than at any time in my recent memory.”

While teams often wait until closer to the deadline to make big moves, Cashman could feel a greater impulse to act after watching this latest performance by Gray.

Gray worked effortlessly through the first two batters of Saturday’s game, but that changed irrevocably during an eight-pitch at-bat to J.D. Martinez, who slapped a base hit up the middle. Gray then walked Mitch Moreland and surrendered a single to Xander Bogaerts to load the bases, bringing Devers to the plate.

Devers, the second-year third baseman, lashed a 1-2 breaking ball from Gray the opposite way, into the seats beyond the left-field wall for his second grand slam this season.

“I put us in too big a hole to dig out of,” Gray said.

When the cheers of the Red Sox fans died down and Gray finally secured the third out of the inning, he walked to the dugout with boos cascading over him. He heard more of the same in the second inning after he gave up two runs, and when he was removed from the game in the third.

Aaron Boone, the Yankees manager, said he still had faith in Gray. “I think he has what it takes to pitch here and to pitch here successfully,” Boone said.

Sale, meanwhile, sliced through the Yankees’ lineup, using a fastball that at times registered 100 miles per hour and his sweeping slider to overpower and baffle the Yankee hitters. He struck out Aaron Judge and Gleyber Torres, who was batting fourth for the first time, three times each.

INSIDE PITCH

Austin Romine strained his left hamstring and had a cautionary magnetic resonance imaging test, the Yankees said, and it came back negative. The Yankees were already without their first-string catcher, Gary Sanchez, who is on the disabled list with a strained groin. … Pitcher Masahiro Tanaka, who has been on the disabled list for three weeks with strained hamstrings, is scheduled to make a rehabilitation start at Class AAA Scranton/Wilkes-Barre.

Correction:

An earlier version of this article misstated the earned run average for Sonny Gray at home this year. It is 8.25, not 7.75.

A version of this article appears in print on , on Page SP8 of the New York edition with the headline: No Ignoring Yanks’ Top Need: Starting Pitching . Order Reprints | Today’s Paper | Subscribe